The present invention relates to a method for determining whether or not connectors, through which a control device is connected to various sensors, actuators and the like, are properly connected in an airbag inflation control system, a seat-belt pretension system, and the like of a car.
Cars are provided with various safety devices for ensuring the safety of passengers in the event of an accident such as a collision. Examples of the devices are an airbag device and a seat belt device. The former protects a passenger by inflating an airbag when an accident, such as a collision, is detected. The latter protects a passenger by a seat belt firmly restraining the passenger in the seat when the accident, such as the collision, is detected or anticipated.
In order for such an airbag device or seat belt device to operate as intended, a control device (Electronic Control Unit; hereinafter referred to as xe2x80x9cECUxe2x80x9d) is installed. Various sensors are provided so as to send necessary information for these ECUs to detect or anticipate an accident, or to determine a control mode. Such sensors include, for example, a seat load meter, an acceleration sensor, an inter-vehicle distance or vehicle gap sensor, a seat-belt tension sensor, and a passenger detection sensor.
Normally, signals from these sensors are transmitted to connectors on a housing of the ECU via cables. Similarly, actuators, such as an airbag device and a seat-belt winding device, are normally connected to the housing of the ECU by connectors via cables. When signals from the sensors and actuators are thus connected to the housing of the ECU, it is possible that connectors connected to cables of certain sensors or actuators may not be connected to correct connectors disposed on the housing of the ECU, that is, connected to connectors to which another sensor or actuator is supposed to be connected.
Such an event may occur even in general electric devices. Common measures against such an event are to use connectors with different shapes and to place pins at different positions so that each connector can not be mechanically connected to wrong connectors.
The above measures, however, are not perfect solution. For example, in a case in which a wrong connector is inadvertently attached to a cable of a sensor, when the sensor is connected to an ECU, it can be connected to a wrong position of the ECU. As a result, the sensor is connected to a signal line of another sensor or actuator. In such a case, of course, the ECU can not operate properly.
The present invention has been made in view of such circumstances, and an object of the invention is to provide a method for reliably ensuring that a device, such as a sensor or an actuator, is connected to a proper connector on a control device, and if the device is connected to a wrong connector, such a wrong connection is surely detected.
Further objects and advantages of the invention will be apparent from the following description of the invention.
To solve the above problems, the present invention provides a method for detecting a connector that improperly connects a device, such as a sensor, to a control device. In the method, the device is provided with an electrical identification signal, and the control device reads the identification signal of the device via the connector. Accordingly, it can be determined that the connector is improperly connected when a correspondence between the connector and the identification of the device is not normal.
In the method, the control device reads the identification signals of various devices via connectors, and determines that the connector is improperly connected when the correspondence between the connector and the device is not normal. This makes it possible to reliably detect that a certain device is connected to an improper connector, and to prevent the control device from malfunctioning.